[Usage] When to Install league/flysystem-bundle vs league/flysystem

[cancan101]

This is a usage question / suggestion for doc improvement:

When do I need to (explicitly) install league/flysystem-bundle vs league/flysystem vs one of the specific adapters (e.g. league/flysystem-azure-blob-storage)?

I am using Symfony by way of Pimcore and have set up a flystem.yaml:

flysystem:
    storages:
        pimcore.asset.storage:
            adapter: azure

I am not otherwise directly calling any of the league supplied PHP directly.